Floating offshore wind turbines pave the way to accessing deep-water regions with abundant wind resources. However, they face specific control challenges, such as the negative damping problem and increased model complexity. Since model-based control is becoming increasingly demanding, a model-free, data-driven approach is considered. Additionally, floating wind turbines are susceptible to rough environmental disturbances. Feedforward information, such as wave elevation measurements from wave radars, may be included in the controller to lessen the impact of disturbances. Although waves have been shown to increase rotor speed oscillations and turbine loads, wave-preview-based methods have only recently been explored. To this end, this paper first proposes a modified Data-enabled Predictive Control formulation that includes past and future information about measurable disturbances. The feasibility of this control strategy is then demonstrated for floating wind turbines through mid-fidelity simulations. The model-free, feedforward controller uses a preview of wave forces acting on the floating platform and aims for rotor speed regulation. Simulations indicate that the data-driven approach has potential for floating wind turbine control, and including wave feedforward action reduces the amplitude of rotor speed oscillations.

Floating wind energy has attracted substantial interest since it enables the deployment of renewable wind energy in deeper waters. However, floating wind turbines are subjected to disturbances, predominantly from turbulence in the wind and waves hitting the platform. Wave disturbances cause undesired oscillations in speed and increase structural loading. This paper focuses on mitigating these disturbance effects with feedforward control using knowledge of the incoming wavefield. The control problem is formulated in an H∞ optimization framework designing two wave feedforward controllers: one to reduce rotor speed oscillations, and the other one to minimize the platform pitch motion. Mid-fidelity time-domain simulations demonstrate the improved performance of the proposed control algorithm regarding wave disturbance mitigation at the cost of higher actuator duty.

The control of Floating Wind Turbines (FWTs) is challenging, as they possess much lower natural frequencies related to the structure's rigid body motion, which creates an undesirable coupling between tower motion and the blade pitch control. As a result, the tower motion is negatively damped triggering instability. This is because of the presence of Right Half Plane Zeros (RHPZs) imposing fundamental limitation on the control bandwidth. To address this problem, different solutions were proposed with varying control structures ranging from Single-Input, Single-Output (SISO) controllers to Multiple-input, Multiple-output (MIMO) ones. In this paper, a new control structure, of Single-Input, Multiple-Output (SIMO) is proposed that is able to lift the bandwidth limitation, while using simple elements that match the industry demands.